KYIV - Residents in Kyiv and other Ukrainian cities are having to cope without hot water after the government switched off communal boilers in residential housing blocks to save energy. This development comes amid growing fears about Ukraine’s ability to survive the coming winter following Russia's decision in June to cut off gas supplies. In response, Ukrainians are deploying a new weapon in their gas war with Moscow.

In a quiet residential park in the suburbs of Kyiv, Natascha and her one-year-old son Sascha enjoy the warm sunshine. But back home, Natascha says looking after an infant is difficult now that the hot water supply has been cut off.

“I can't bathe my baby,” she says. “I can't wash the dishes.The basic things that a human needs are hot water, heating and electricity. If you take away those basic things, how can a person live?”

Kyiv’s Soviet-era housing blocks are supplied with communal heating and hot water from municipal boilers. The system is shut off for a week every summer for cleaning.

But authorities announced this week that the hot water won’t be turned on again until October, to conserve gas supplies for winter. In just a few months, the temperatures will plunge to around minus-20 degrees Celsius.

In past years, Ukraine has relied on cheap gas from Russia, but Moscow cut off supplies in June in a dispute over debt payments.

The deputy chairman of Ukraine’s state-run gas firm Naftogaz, Oleksandr Todiichuk, said his countrymen must prepare for tough times.

He says Ukraine faces a really challenging winter. Right now there are about 15 billion cubic meters of gas in the underground storage tanks, which is about a third of what Ukraine would normally consume this year, he says.

Worsening the problem, Todiichuk said, Ukrainian Black Sea gas platforms are now under Russian control following Moscow’s forceful takeover of Crimea in March. The gas is being pumped back to Russia.

Faced with an energy crisis, Ukraine is deploying a new weapon in its gas war with Russia: energy efficiency.

A movement called Energy Evolution: Conserve Energy, Save Ukraine aims to highlight everyday energy waste - and how it can be reduced.

Polina Bashkina, the organization's spokesperson, says the first goal is to inform Ukrainians that saving energy is good for the economy. The second, she says, is to lessen the shock when gas costs rise, because they are going to keep increasing, and in autumn they will see much higher bills. The third, long-term goal, she says, is to make Ukraine an energy independent country.

If Ukrainians treat energy efficiently, she says, they could reduce their needs by around 45-48 percent. A reduction of that magnitude would mean a drop in demand of 29 billion cubic meters, which more than Ukraine bought from Russia in 2013.

Neighboring Slovakia has said it will allow the so-called reverse flow of gas from the EU into Ukraine - potentially offering Kyiv a winter lifeline. In the meantime, campaigners say Ukrainian citizens must cut back on energy use and break their dependence on Russia.